// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/threading/thread.h"

#include <stddef.h>

#include <vector>

#include "base/bind.h"
#include "base/location.h"
#include "base/single_thread_task_runner.h"
#include "base/synchronization/waitable_event.h"
#include "base/third_party/dynamic_annotations/dynamic_annotations.h"
#include "build/build_config.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "testing/platform_test.h"

using base::Thread;

typedef PlatformTest ThreadTest;

namespace {

void ToggleValue(bool* value)
{
    ANNOTATE_BENIGN_RACE(value, "Test-only data race on boolean "
                                "in base/thread_unittest");
    *value = !*value;
}

class SleepInsideInitThread : public Thread {
public:
    SleepInsideInitThread()
        : Thread("none")
    {
        init_called_ = false;
        ANNOTATE_BENIGN_RACE(
            this, "Benign test-only data race on vptr - http://crbug.com/98219");
    }
    ~SleepInsideInitThread() override { Stop(); }

    void Init() override
    {
        base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(500));
        init_called_ = true;
    }
    bool InitCalled() { return init_called_; }

private:
    bool init_called_;
};

enum ThreadEvent {
    // Thread::Init() was called.
    THREAD_EVENT_INIT = 0,

    // The MessageLoop for the thread was deleted.
    THREAD_EVENT_MESSAGE_LOOP_DESTROYED,

    // Thread::CleanUp() was called.
    THREAD_EVENT_CLEANUP,

    // Keep at end of list.
    THREAD_NUM_EVENTS
};

typedef std::vector<ThreadEvent> EventList;

class CaptureToEventList : public Thread {
public:
    // This Thread pushes events into the vector |event_list| to show
    // the order they occured in. |event_list| must remain valid for the
    // lifetime of this thread.
    explicit CaptureToEventList(EventList* event_list)
        : Thread("none")
        , event_list_(event_list)
    {
    }

    ~CaptureToEventList() override { Stop(); }

    void Init() override { event_list_->push_back(THREAD_EVENT_INIT); }

    void CleanUp() override { event_list_->push_back(THREAD_EVENT_CLEANUP); }

private:
    EventList* event_list_;
};

// Observer that writes a value into |event_list| when a message loop has been
// destroyed.
class CapturingDestructionObserver
    : public base::MessageLoop::DestructionObserver {
public:
    // |event_list| must remain valid throughout the observer's lifetime.
    explicit CapturingDestructionObserver(EventList* event_list)
        : event_list_(event_list)
    {
    }

    // DestructionObserver implementation:
    void WillDestroyCurrentMessageLoop() override
    {
        event_list_->push_back(THREAD_EVENT_MESSAGE_LOOP_DESTROYED);
        event_list_ = NULL;
    }

private:
    EventList* event_list_;
};

// Task that adds a destruction observer to the current message loop.
void RegisterDestructionObserver(
    base::MessageLoop::DestructionObserver* observer)
{
    base::MessageLoop::current()->AddDestructionObserver(observer);
}

// Task that calls GetThreadId() of |thread|, stores the result into |id|, then
// signal |event|.
void ReturnThreadId(base::Thread* thread,
    base::PlatformThreadId* id,
    base::WaitableEvent* event)
{
    *id = thread->GetThreadId();
    event->Signal();
}

} // namespace

TEST_F(ThreadTest, Restart)
{
    Thread a("Restart");
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
    EXPECT_TRUE(a.Start());
    EXPECT_TRUE(a.message_loop());
    EXPECT_TRUE(a.IsRunning());
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
    EXPECT_TRUE(a.Start());
    EXPECT_TRUE(a.message_loop());
    EXPECT_TRUE(a.IsRunning());
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
}

TEST_F(ThreadTest, StartWithOptions_StackSize)
{
    Thread a("StartWithStackSize");
    // Ensure that the thread can work with only 12 kb and still process a
    // message.
    Thread::Options options;
#if defined(ADDRESS_SANITIZER)
    // ASan bloats the stack variables and overflows the 12 kb stack.
    options.stack_size = 24 * 1024;
#else
    options.stack_size = 12 * 1024;
#endif
    EXPECT_TRUE(a.StartWithOptions(options));
    EXPECT_TRUE(a.message_loop());
    EXPECT_TRUE(a.IsRunning());

    bool was_invoked = false;
    a.task_runner()->PostTask(FROM_HERE, base::Bind(&ToggleValue, &was_invoked));

    // wait for the task to run (we could use a kernel event here
    // instead to avoid busy waiting, but this is sufficient for
    // testing purposes).
    for (int i = 100; i >= 0 && !was_invoked; --i) {
        base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(10));
    }
    EXPECT_TRUE(was_invoked);
}

TEST_F(ThreadTest, TwoTasks)
{
    bool was_invoked = false;
    {
        Thread a("TwoTasks");
        EXPECT_TRUE(a.Start());
        EXPECT_TRUE(a.message_loop());

        // Test that all events are dispatched before the Thread object is
        // destroyed.  We do this by dispatching a sleep event before the
        // event that will toggle our sentinel value.
        a.task_runner()->PostTask(
            FROM_HERE, base::Bind(static_cast<void (*)(base::TimeDelta)>(&base::PlatformThread::Sleep), base::TimeDelta::FromMilliseconds(20)));
        a.task_runner()->PostTask(FROM_HERE,
            base::Bind(&ToggleValue, &was_invoked));
    }
    EXPECT_TRUE(was_invoked);
}

TEST_F(ThreadTest, StopSoon)
{
    Thread a("StopSoon");
    EXPECT_TRUE(a.Start());
    EXPECT_TRUE(a.message_loop());
    EXPECT_TRUE(a.IsRunning());
    a.StopSoon();
    a.StopSoon();
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
}

TEST_F(ThreadTest, ThreadName)
{
    Thread a("ThreadName");
    EXPECT_TRUE(a.Start());
    EXPECT_EQ("ThreadName", a.thread_name());
}

TEST_F(ThreadTest, ThreadId)
{
    Thread a("ThreadId0");
    Thread b("ThreadId1");
    a.Start();
    b.Start();

    // Post a task that calls GetThreadId() on the created thread.
    base::WaitableEvent event(base::WaitableEvent::ResetPolicy::AUTOMATIC,
        base::WaitableEvent::InitialState::NOT_SIGNALED);
    base::PlatformThreadId id_from_new_thread;
    a.task_runner()->PostTask(
        FROM_HERE, base::Bind(ReturnThreadId, &a, &id_from_new_thread, &event));

    // Call GetThreadId() on the current thread before calling event.Wait() so
    // that this test can find a race issue with TSAN.
    base::PlatformThreadId id_from_current_thread = a.GetThreadId();

    // Check if GetThreadId() returns consistent value in both threads.
    event.Wait();
    EXPECT_EQ(id_from_current_thread, id_from_new_thread);

    // A started thread should have a valid ID.
    EXPECT_NE(base::kInvalidThreadId, a.GetThreadId());
    EXPECT_NE(base::kInvalidThreadId, b.GetThreadId());

    // Each thread should have a different thread ID.
    EXPECT_NE(a.GetThreadId(), b.GetThreadId());
}

TEST_F(ThreadTest, ThreadIdWithRestart)
{
    Thread a("ThreadIdWithRestart");
    base::PlatformThreadId previous_id = base::kInvalidThreadId;

    for (size_t i = 0; i < 16; ++i) {
        EXPECT_TRUE(a.Start());
        base::PlatformThreadId current_id = a.GetThreadId();
        EXPECT_NE(previous_id, current_id);
        previous_id = current_id;
        a.Stop();
    }
}

// Make sure Init() is called after Start() and before
// WaitUntilThreadInitialized() returns.
TEST_F(ThreadTest, SleepInsideInit)
{
    SleepInsideInitThread t;
    EXPECT_FALSE(t.InitCalled());
    t.StartAndWaitForTesting();
    EXPECT_TRUE(t.InitCalled());
}

// Make sure that the destruction sequence is:
//
//  (1) Thread::CleanUp()
//  (2) MessageLoop::~MessageLoop()
//      MessageLoop::DestructionObservers called.
TEST_F(ThreadTest, CleanUp)
{
    EventList captured_events;
    CapturingDestructionObserver loop_destruction_observer(&captured_events);

    {
        // Start a thread which writes its event into |captured_events|.
        CaptureToEventList t(&captured_events);
        EXPECT_TRUE(t.Start());
        EXPECT_TRUE(t.message_loop());
        EXPECT_TRUE(t.IsRunning());

        // Register an observer that writes into |captured_events| once the
        // thread's message loop is destroyed.
        t.task_runner()->PostTask(
            FROM_HERE, base::Bind(&RegisterDestructionObserver, base::Unretained(&loop_destruction_observer)));

        // Upon leaving this scope, the thread is deleted.
    }

    // Check the order of events during shutdown.
    ASSERT_EQ(static_cast<size_t>(THREAD_NUM_EVENTS), captured_events.size());
    EXPECT_EQ(THREAD_EVENT_INIT, captured_events[0]);
    EXPECT_EQ(THREAD_EVENT_CLEANUP, captured_events[1]);
    EXPECT_EQ(THREAD_EVENT_MESSAGE_LOOP_DESTROYED, captured_events[2]);
}

TEST_F(ThreadTest, ThreadNotStarted)
{
    Thread a("Inert");
    EXPECT_FALSE(a.task_runner());
}

TEST_F(ThreadTest, MultipleWaitUntilThreadStarted)
{
    Thread a("MultipleWaitUntilThreadStarted");
    EXPECT_TRUE(a.Start());
    // It's OK to call WaitUntilThreadStarted() multiple times.
    EXPECT_TRUE(a.WaitUntilThreadStarted());
    EXPECT_TRUE(a.WaitUntilThreadStarted());
}
